Share logic in BaseTextInputShadowNode to calculate placeholder string

packages/react-native/ReactCommon/react/renderer/components/textinput/BaseTextInputShadowNode.h

@@ -97,13 +97,7 @@ class BaseTextInputShadowNode : public ConcreteViewShadowNode<
     auto attributedString = getAttributedString(layoutContext);
 
     if (attributedString.isEmpty()) {
-      auto placeholderString = !props.placeholder.empty()
-          ? props.placeholder
-          : BaseTextShadowNode::getEmptyPlaceholder();
-      auto textAttributes =
-          props.getEffectiveTextAttributes(layoutContext.fontSizeMultiplier);
-      attributedString.appendFragment(
-          {std::move(placeholderString), textAttributes, {}});
+      attributedString = getPlaceholderAttributedString(layoutContext);
     }
 
     // Yoga expects a baseline relative to the Node's border-box edge instead of
@@ -120,6 +114,32 @@ class BaseTextInputShadowNode : public ConcreteViewShadowNode<
         top;
   }
 
+  /*
+   * Determines the constraints to use while measure the underlying text
+   */
+  LayoutConstraints getTextConstraints(
+      const LayoutConstraints& layoutConstraints) const {
+    if (BaseShadowNode::getConcreteProps().multiline) {
+      return layoutConstraints;
+    } else {
+      // A single line TextInput acts as a horizontal scroller of infinitely
+      // expandable text, so we want to measure the text as if it is allowed to
+      // infinitely expand horizontally, and later clamp to the constraints of
+      // the input.
+      return LayoutConstraints{
+          .minimumSize = layoutConstraints.minimumSize,
+          .maximumSize =
+              Size{
+                  .width = std::numeric_limits<Float>::infinity(),
+                  .height = layoutConstraints.maximumSize.height,
+              },
+          .layoutDirection = layoutConstraints.layoutDirection,
+      };
+    }
+  }
+
+  std::shared_ptr<const TextLayoutManager> textLayoutManager_;
+
  private:
   /*
    * Creates a `State` object if needed.
@@ -150,48 +170,22 @@ class BaseTextInputShadowNode : public ConcreteViewShadowNode<
   AttributedString getAttributedString(
       const LayoutContext& layoutContext) const {
     const auto& props = BaseShadowNode::getConcreteProps();
-    auto textAttributes =
+    const auto textAttributes =
         props.getEffectiveTextAttributes(layoutContext.fontSizeMultiplier);
-    auto attributedString = AttributedString{};
 
+    AttributedString attributedString;
     attributedString.appendFragment(AttributedString::Fragment{
         .string = props.text,
         .textAttributes = textAttributes,
-        // TODO: Is this really meant to be by value?
         .parentShadowView = ShadowView(*this)});
 
     auto attachments = BaseTextShadowNode::Attachments{};
     BaseTextShadowNode::buildAttributedString(
         textAttributes, *this, attributedString, attachments);
     attributedString.setBaseTextAttributes(textAttributes);
-
     return attributedString;
   }
 
-  /*
-   * Determines the constraints to use while measure the underlying text
-   */
-  LayoutConstraints getTextConstraints(
-      const LayoutConstraints& layoutConstraints) const {
-    if (BaseShadowNode::getConcreteProps().multiline) {
-      return layoutConstraints;
-    } else {
-      // A single line TextInput acts as a horizontal scroller of infinitely
-      // expandable text, so we want to measure the text as if it is allowed to
-      // infinitely expand horizontally, and later clamp to the constraints of
-      // the input.
-      return LayoutConstraints{
-          .minimumSize = layoutConstraints.minimumSize,
-          .maximumSize =
-              Size{
-                  .width = std::numeric_limits<Float>::infinity(),
-                  .height = layoutConstraints.maximumSize.height,
-              },
-          .layoutDirection = layoutConstraints.layoutDirection,
-      };
-    }
-  }
-
   /*
    * Returns an `AttributedStringBox` which represents text content that should
    * be used for measuring purposes. It might contain actual text value,
@@ -217,23 +211,33 @@ class BaseTextInputShadowNode : public ConcreteViewShadowNode<
         : getAttributedString(layoutContext);
 
     if (attributedString.isEmpty()) {
-      const auto& props = BaseShadowNode::getConcreteProps();
-      auto placeholder = props.placeholder;
-      // Note: `zero-width space` is insufficient in some cases (e.g. when we
-      // need to measure the "hight" of the font).
-      // TODO T67606511: We will redefine the measurement of empty strings as
-      // part of T67606511
-      auto string = !placeholder.empty()
-          ? placeholder
-          : BaseTextShadowNode::getEmptyPlaceholder();
-      auto textAttributes =
-          props.getEffectiveTextAttributes(layoutContext.fontSizeMultiplier);
-      attributedString.appendFragment({string, textAttributes, {}});
+      attributedString = getPlaceholderAttributedString(layoutContext);
     }
     return AttributedStringBox{attributedString};
   }
 
-  std::shared_ptr<const TextLayoutManager> textLayoutManager_;
+  // For measurement purposes, we want to make sure that there's at least a
+  // single character in the string so that the measured height is greater
+  // than zero. Otherwise, empty TextInputs with no placeholder don't
+  // display at all.
+  // TODO T67606511: We will redefine the measurement of empty strings as part
+  // of T67606511
+  AttributedString getPlaceholderAttributedString(
+      const LayoutContext& layoutContext) const {
+    const auto& props = BaseShadowNode::getConcreteProps();
+
+    AttributedString attributedString;
+    auto placeholderString = !props.placeholder.empty()
+        ? props.placeholder
+        : BaseTextShadowNode::getEmptyPlaceholder();
+    auto textAttributes =
+        props.getEffectiveTextAttributes(layoutContext.fontSizeMultiplier);
+    attributedString.appendFragment(
+        {.string = std::move(placeholderString),
+         .textAttributes = textAttributes,
+         .parentShadowView = {}});
+    return attributedString;
+  }
 };
 
 } // namespace facebook::react